1. Field of the Invention
The present invention relates to ground contacting rollers commonly used on reel type mower head assemblies designed for golf course or cemetary mowing or other mowing where precision cutting is required. The present invention relates more specifically to a grooved roller having a configuration which provides greater cutting accuracy and efficiency for use on fairway and green cutting as well as off-fairway mowing particularly when used to control the mower blade height adjustment.
2. Description of the Prior Art
Although smooth-surface lawn mower rollers have been used in the past and are still in widespread use, it is well recognized that providing some form of annular grooving or relief on the roller surface enhances the performance and reliability of the roller. When used as front rollers, i.e. ahead of the reel mower blade, prior art grooved rollers have achieved some degree of success in lessening the amount of grass that is laid flat prior to cutting. Other problems, such as the accumulation of debris in the nature of acorns, pine cones, small stones and other objects, are however heightened by the presence of grooves in the roller. Since most greens and lawns are frequently mowed following watering or for some reason are in a wet condition, the problem of grass clipping accumulation on the roller surface also becomes significant. This problem has not been solved by prior art grooved roller designs. The front roller, which precedes the cutting reel, is vertically adjustable relative to the mower blade and acts as a depth gauge to control the height and accuracy of the cut. Since fairways are maintained at approximately 1/2 inch height and greens even less, any appreciable build-up tending to increase the diameter of the roller becomes a very real problem. Since watering of golf course greens and fairways is done at night and most mowing is done during the morning hours, the problem is persistent. Under these conditions the depth gauge rollers may sometimes even double in diameter with the accumulation of wet grass clippings requiring frequent shut-down and cleaning, especially on green areas.
U.S. Pat. No. 5,394,681 to Nolan et al and U.S. Pat. No. 5,511,365 to Rice are examples of roller configurations which utilize relatively shallow grooves, sometimes referred to as a wave configuration. These grooved rollers avoid some of the problem of grass laydown but do not solve the problem of debris accumulation and wet grass clipping build-up. The roller of the Nolan U.S. Pat. No. 5,394,681, for instance, utilizes a fairly shallow groove or depression, which is susceptible to debris and grass clipping build-up which interferes with the depth gauge functioning of the roller. Additionally, since the surface on the Nolan roller is in the form of a shallow wave, the depth of the grooves is insufficient to accommodate the grass height on fairways which may be in the order of 1/2 inch and certainly does no more than lay the grass down when operating outside the greens and fairways. The Rice patent which also utilizes a wave type pattern on the roller surface when viewed in cross section suffers from the same shortcomings since the wave troughs are extremely shallow.
Other attempts at shallow groove rollers such as the Akgulian et al U.S. Pat. No. 3,662,528 and the Olney et al U.S. Pat. No. 3,895,481 suffer from the same shortcomings as the prior two patents discussed. Additionally these patents utilize a roller configuration wherein the edges of the raised portions of the roller surface are sharp and tend to act as a scraper or turf cutting element when the mower is turned. The presence of sharp edges and the vertical sides of the small grooves of these patents also aggravate the debris build-up and grass clipping accumulation problem.
Still other patents such as U.S. Pat. No. 4,947,630 to Rich et al and British Patents Nos. 1384 and 3201, although using a somewhat deeper groove, utilize a groove configuration with opposing vertical or curved sides which aggravates the debris collection problem. Additionally, the Rich et al patent utilizes an assembly of sharp edged discs to form the grooves, severely aggravating the problem of tearing the turf when the mower is turned.
It must also be borne in mind that substantial weight is carried on the relatively small diameter depth gauge rollers of the type under consideration. Overall roller distortion may result from rough terrain or obstructions and, if the material of the roller is thin enough, mushrooming of the ridge portions of the rollers may occur. Both of these phenomena result in increased tendency for debris collection and grass clipping build-up. In the Rich et al patent an attempt is made to address the problem of debris build-up by the use of a transversely extending rod 22 located adjacent the surface of the ridges of the roller. The problem with this type of roller clearing is that, the roller body, roller surface and the rod 22 may all become distorted, rendering the cleaning rod ineffective.